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Nokia 2-mm DC Charging Interface Specification

F O R U M N O K I A

Version 1.2; August 22, 2006

Charging Interface

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Nokia 2-mm DC Charging Interface Specification 2

Copyright © 2005–2006 Nokia Corporation. All rights reserved.

Nokia and Forum Nokia are registered trademarks of Nokia Corporation. Other product and company names mentioned herein may be trademarks or trade names of their respective owners.

Disclaimer

The information in this document is provided “as is,” with no warranties whatsoever, including any warranty of merchantability, fitness for any particular purpose, or any warranty otherwise arising out of any proposal, specification, or sample. Furthermore, information provided in this document is preliminary, and may be changed substantially prior to final release. This document is provided for informational purposes only.

Nokia Corporation disclaims all liability, including liability for infringement of any proprietary rights, relating to implementation of information presented in this document. Nokia Corporation does not warrant or represent that such use will not infringe such rights.

Nokia Corporation retains the right to make changes to this specification at any time, without notice.

License

A license is hereby granted to download and print a copy of this specification for personal use only. No other license to any other intellectual property rights is granted herein.

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Contents

1 Introduction................................................................................................................................................ 5 2 General electrical specifications ............................................................................................................ 6

2.1 General.........................................................................................................................................................6 2.2 Charger output capacitance..................................................................................................................6 2.3 Maximum voltage and current values...............................................................................................7 2.4 Maximum output ripple voltage .........................................................................................................8 2.5 Charger output conducted emissions ...............................................................................................9 2.6 Leakage current of AC chargers ...........................................................................................................9

3 Electrical specification for constant current type chargers ..........................................................10 3.1 Charging voltage — current window.............................................................................................10 3.2 U/I corner point......................................................................................................................................10 3.3 Current linearity.....................................................................................................................................10

4 Electrical specification for special chargers......................................................................................12 4.1 Charging voltage — current window.............................................................................................12 4.2 Charging voltage rise time.................................................................................................................12 4.3 Current linearity recommendation..................................................................................................12

5 Accessories connected between the charger and the mobile device........................................14 5.1 Accessory interfaces .............................................................................................................................14 5.2 Electrical specifications for accessories .........................................................................................14 5.3 Booting up the mobile device when connected to an accessory..........................................15 5.4 Charger identification..........................................................................................................................15

6 Charger identification method ............................................................................................................17 6.1 Charger voltage measurement .........................................................................................................17

7 Mechanical specification........................................................................................................................18 8 Terms and abbreviations.......................................................................................................................20 Appendix A: Artificial load.............................................................................................................................21 Evaluate this resource....................................................................................................................................22

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Change history

June 16, 2005 Version 1.0 Initial document release

October 26, 2005 Version 1.1 Sections 2.4 and 4.1 updated

August 22, 2006 Version 1.2 Figure 13 updated

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1 Introduction

This document specifies the electrical and mechanical charging interface between Nokia mobile devices and power-supply accessories, specifically chargers. It also defines the charger-identification process of these mobile devices. The specification is valid only for devices with a 2-mm charging interface.

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2 General electrical specifications

2.1 General

The interface supports the following two types of two-wire chargers:

1. Constant current chargers (standard charger)

A constant current type charger may have a wide output current range and the current may change with other parameters. The specifications for a constant current charger appear in Chapter 3, “Electrical specification for constant current type chargers.”

2. Special chargers

Special chargers take charging energy from a solar cell or hand-operated generator, for example. External charging conditions have a great impact on the charging current — the waveform of the charging current is unknown and charging can even be stopped. Battery charging time may vary considerably. Specifications for special chargers are described in Chapter 4, “Electrical specification for special chargers.”

2.2 Charger output capacitance

The capacitance in charger output causes charging current spikes when the charger's load changes. Low-capacitance values are recommended if possible. Maximum charger output filter capacitor size is 1000 µF if the charger VMAX-OUTPUT is less than 7 V. For output voltages of 7 V – 9.3 V, the maximum capacitance value decreases linearly so that for a 9.3 V charger, maximum output capacitance is 700 µF.

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6

7

8

99.3

Char

g er m

axim

u m o

utp u

tv o

ltage

Maximum recommendedoutput capacitance

500 700 1000 uF

V

5

10

4

Figure 1: Maximum charger output capacitance

2.3 Maximum voltage and current values

Maximum charger output overshoot 16 V

Maximum reverse voltage at charger output 1 V

Maximum time for constant current type charger to achieve steady state value (U and I) after load change

10 ms

Maximum duration of charging current overshoot peak value greater than 1.1 A

5 ms

Table 1: Limits for maximum voltage and settling time

* Limits are also valid for a damaged charger. * These voltage and current limits must be doubly insured; in other words, if the general charging voltage control system fails, there must be a backup limiter inside the charger.

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Current

1100 mA

Time

0 mA

Max. 5 ms

Nominal output current

Max. 10 ms

10%

Mobile device current limit

Figure 2: Maximum duration of charging current overshoot

2.4 Maximum output ripple voltage

The maximum acceptable output ripple voltage with maximum output current (constant current mode, 2.5 V < Uout < 5.5 V) is 300 mV (root mean square, RMS).

The maximum acceptable output peak-to-peak ripple voltage is separated to four frequency areas. A summary of ripple voltages with different frequencies over the full frequency area (0 – 1 MHz) is 800 mVP-P. Ripple voltage shall be measured using 0 – 6 kΩ resistive load.

Note: Charging voltage, including ripple, may never have peak values outside the U/I window for charger output.

Frequency Maximum voltage

0 - 20 Hz 200 mVp-p

20 Hz - 200 Hz 200 mVp-p

200 Hz - 20 kHz 200 mVp-p

20 kHz – 1 MHz 400 mVp-p

Table 2: Maximum ripple voltage by frequency

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Frequency 200Hz - 20 kHzmax. VRIPPLE P-P 200 mV

Frequency 0 - 20 Hzmax. VRIPPLE P-P 200 mV All frequencies together

max. VRIPPLE P-P 800 mV

Figure 3: Maximum peak-to-peak ripple voltage

2.5 Charger output conducted emissions

Frequency range Maximum EMI disturbances

1 MHz – 80 MHz -40 dBm to -65 dBm linearly

80 MHz – 150 MHz -65 dBm

Table 3: Maximum conducted disturbances

The limits for conducted emissions from charger output are presented in Table 3 and Figure 4. The charger shall be connected to artificial load (Appendix A: Artificial load) during measurement.

LeveldBm

1 MHz 80 MHz 150 MHz

-30

-40

-50

-60

-70

-80

-90

Frequency

Figure 4: Maximum conducted emissions

2.6 Leakage current of AC chargers

Maximum leakage current from AC mains to the mobile device through the charger is 5 µA.

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3 Electrical specification for constant current type chargers

3.1 Charging voltage — current window

The minimum charging current is 300 mA. During charging, the current and voltage must fit within the charging window shown in Figure 5.

The only time that the charging voltage is allowed to go out of the charging current/voltage window is in a load change situation (see Section 2.3, “Maximum voltage and current values").

1

2

3

4

5

6

7

8

9

10

Volta

ge V

100 200 300 400 500 600 700 800 900 1000 1100 1200

Current mA

1.0 V

90950

9.3

5.7 5.54 V

.

Figure 5: Charging current/voltage window for constant current type chargers

3.2 U/I corner point

The U/I curve corner point when the constant voltage mode changes to the constant current mode is greater than 5.54 V if the current is more than 300 mA.

3.3 Current linearity

Maximum current fluctuation under stable temperature condition is 30 percent when the charger output voltage changes from 3.5 V to 5.0 V (for example, 500 mA - 30% = 350 mA) when input voltage and ambient temperature stay constant.

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1

2

3

4

5

6

7

8

Volta

ge V

100 200 300 400 500 600 700 800

Current mA

5.0 V

3.5 V

Figure 6: Current linearity specification

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4 Electrical specification for special chargers

4.1 Charging voltage — current window

The minimum charging current is 90 mA. During charging, the current and the voltage must fit within the charging window shown in Figure 7. The only time that the charging voltage is allowed to go out of the charging current/voltage window is in a load change situation (see Section 2.3, "Maximum voltage and current values").

Products having high boot-up current consumption may be unable to boot-up with empty battery even if special charger, which provides only small current, is connected.

1

2

3

4

5

6

7

Volta

ge V

100 200 300 400 500 600 700 800 900 1000 1100 1200

1.0 V

90

5.2

950

1.6

4.65

Figure 7: Charging current/voltage window for special chargers

4.2 Charging voltage rise time

Special chargers don't have a time limit on how fast the charger must archive the steady state value (U and I) after load change. Charging will not start until the charger output voltage reaches 4.65 V. The charger must provide a minimum charging current according to Figure 8, even if the voltage is rising slowly.

4.3 Current linearity recommendation

Following current linearity recommendations yields the best results between chargers and Nokia mobile devices, thus good current linearity should be the goal when designing new chargers. However, adhering to the specification is not mandatory if doing so is impossible due to the structure of a specific charger.

Charging current linearity is divided into two parts, based on the charging current change frequency. For fICHAR < ½ Hz, the maximum allowed current slew rate is 0.28*ICHAR A/sec. For fICHAR > ½ Hz, the maximum charge current crest factor is < 1.14.

Crest factor = IPEAK / IRMS.

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800 100090 400

20

40

60

80

100

120

140

200 600ICHAR [mA]

Max

imum

pea

k cu

rren

t [m

A]

ICHAR o

ut o

f ran

ge

ICHAR o

ut o

f ran

ge

Allowed peakcurrent

Figure 8: Maximum allowed charging current peaks (crest factor) fICHAR > ½ Hz

200 600 800 1000

50

100

150

200

250

90 400

300

Max

imum

sle

w ra

te [m

A/se

c]

ICHAR [mA]

Allowed currentslew rate

ICHAR o

ut o

f ran

ge

I CHAR o

ut o

f ran

ge

.

Figure 9: Maximum allowed charging current slew rate fICHAR < ½ Hz

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5 Accessories connected between the charger and the mobile device

5.1 Accessory interfaces

An accessory connected between the charger and the mobile device shares energy with that mobile device while taking energy for its own needs. The sharing policy varies based on the type of accessory and the operating conditions. The accessory must always provide an interface to the mobile device that meets this Nokia 2-mm DC Charging Interface Specification. The interface is indicated with dashed lines in Figure 10.

AccessoryCharger Mobile device

Voltage inVCHAR

GND

VCHAR

GND

Accessoryfunctionalities

Figure 10: Accessory/mobile device interface

5.2 Electrical specifications for accessories

Accessories connected between the charger and the mobile device and having direct contact with charging lines (for example, a desk stand), must not disturb the charging or charger identification.

Description Min. Typ. Max. Unit

Ground lead resistance with contacts 0 0.05 Ω

Positive lead resistance 0 0.2 0.40 Ω

Capacitance between charging lines 0 4.0 µF

Table 4: Electrical specification for accessory contacts

Figure 11 shows the U/I window that the accessory must provide to the mobile device.

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1

2

3

4

5

6

7

8

9

10

Volta

ge V

100 200 300 400 500 600 700 800 900 1000 1100 1200

Current mA

1.0 V

90

5.5

950

9.3

5.7

Minimum voltage atmobile device input

Minimum voltage atcharger output

5.54 V5.37 V

Figure 11: Charging current/voltage window for a mobile device

Even if the accessory is powered by a standard, constant current charger, it doesn't need to fulfill the current linearity specification for constant current type chargers (see Section 3.3, "Current linearity")

5.3 Booting up the mobile device when connected to an accessory

While the mobile device is booting up, the accessory connected between the charger and the device must not limit the charging current between the two. Also, it must be possible to boot up the mobile device when there is an accessory connected between the charger and the device and the device's battery is totally empty.

An accessory may have current consumption IMAX = 10mA as long as the charging voltage (VCHAR) is below 3.5 V.

5.4 Charger identification

An accessory connected between the charger and the mobile device must not prevent the device from identifying the charger type correctly. For example, if the accessory is connected to the charger, and the mobile device, which is powered on, is later connected to the accessory, the power consumption of the accessory may result in the wrong charger identification.

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The accessory must limit its power consumption (or use some other method) so that there is a minimum 5.5 V charging voltage available in the charging interface for the mobile device during the first 300 ms after the mobile device is connected to the accessory.

Some old charger types are detected with a 100/120 Hz output ripple voltage. The accessory must not prevent that detection. If the accessory input voltage is a rectified AC voltage, there must be a minimum 5.5 V average charging voltage available for the mobile device during 300 ms after the mobile device is connected to the accessory. The peak-to-peak value of the charging voltage must be more than 2000 mV.

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6 Charger identification method

6.1 Charger voltage measurement

When a charger is connected to the mobile device, the device's system will start the charger-recognition procedure by checking the charger voltage with 1 – 2 mA current. Identification is based on measured average voltage and waveform: 4.65 V – 5.20 V is identified as a special charger and 5.5 V – 9.3 V is identified as a standard charger.

ChargerVoltage

13

12

11

10

9

8

7

6

5

4

3

Special charger

Standardcharger

4.65 V to 5.20 V

5.5 V to 9.3 V

Charger voltage range

Over 9.3 VIllegal voltage

5.2 V - 5.5 V andunder 4.65 V

Illegal voltage Figure 12: Charger identification voltages

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7 Mechanical specification

Figure 13: Mechanical specification for Nokia 2-mm charging plug (outmolding)

The charging voltage is connected to the center pin and the ground is connected to the outer surface of the plug.

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Figure 14: Mechanical specification for Nokia 2-mm charging plug

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8 Terms and abbreviations

Term or abbreviation Meaning

AC Alternating current

CDN Coupling and decoupling network

Crest factor Current peak value/current RMS value

DC Direct current

EMI Electromagnetic interference

ESR Equivalent series resistance

Pop-Port System connector in Nokia mobile devices

PWM Pulse width modulation

RMS Root mean square

Slew rate (U or I) value change/changing time

U/I Voltage/Current

VCHAR Charging voltage

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Appendix A: Artificial load

C1

DC jack

C2 R

In an artificial load circuit:

R value is selected so that charger output is 5.0 V.

C1 value is 4,400 µF – 6,000 µF, low ESR.

C2 value is 1 nF, low ESR.

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